Aspirin use is not associated with metabolic dysfunction associated fatty liver disease in the UK Biobank

This study investigated the association between aspirin use and metabolic dysfunction-associated fatty liver disease (MAFLD). Based on data from the UK Biobank (UKB), this study included a variety of covariates such as age, gender, BMI, lifestyle factors, metabolic indicators and liver function indicators, and assessed the association between aspirin use and MAFLD after balancing the baseline differences by the propensity score matching (PSM) method, and explored the influencing factors by stratified analyses and interaction tests. During a median follow-up period of 9.41 years, among 3,922 participants, aspirin use was not significantly associated with MAFLD after adjusting for a variety of metabolic confounders (OR = 0.97, 95% CI: 0.82–1.15), a finding that was consistent across sensitivity analyses. When BMI was modeled categorically, a significant association was observed only among participants with obesity (BMI ≥ 30 kg/m²; OR 0.69, 95% CI 0.52–0.92), whereas no associations were found in normal-weight or overweight groups. An exploratory interaction was observed between aspirin use and stroke history (aspirin × stroke, OR for interaction = 0.07, 95% CI: 0.008–0.646, P = 0.019). In this observational study, aspirin use was not significantly associated with MAFLD. Exploratory analyses suggested possible heterogeneity according to BMI and stroke history; however, these findings should be considered hypothesis-generating because of multiple comparisons and the small number of participants with a history of stroke. Overall, aspirin use was not significantly associated with MAFLD.